US3630595A - Apparatus for converting linearly polarized radiation into linearly polarized radiation having a plane of polarization varying linearly with time - Google Patents

Apparatus for converting linearly polarized radiation into linearly polarized radiation having a plane of polarization varying linearly with time Download PDF

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Publication number
US3630595A
US3630595A US7634A US3630595DA US3630595A US 3630595 A US3630595 A US 3630595A US 7634 A US7634 A US 7634A US 3630595D A US3630595D A US 3630595DA US 3630595 A US3630595 A US 3630595A
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United States
Prior art keywords
radiation
plane
linearly polarized
polarization
crystal
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Expired - Lifetime
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US7634A
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English (en)
Inventor
Theodorus Hendrikus Peek
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US Philips Corp
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US Philips Corp
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements

Definitions

  • the invention relates to an improved apparatus for converting linearly polarized radiation having an arbitrary plane of polarization into linearly polarized radiation the orientation of the plane of polarization of which varies linearly with time from the initial arbitrary orientation, in which apparatus the radiation passes at least thrice through a birefringent element, at least one of the elements traversed being an electro-optical crystal, while the relative orientations of the elements and the electric voltages applied to the crystals have been suitably chosen.
  • FIGS. I and 4 show an embodiment.
  • a disadvantage of the apparatus shown in FIG. I of the said application is that it requires three electro-optical crystals and comparatively high voltages. To the middle crystal there is applied a voltage having an amplitude which is twice that of the voltage applied to each outer crystal.
  • the apparatus shown in FIG. 4 has the disadvantage that the voltage applied to the crystal is comparatively high.
  • the improvement consists in that a series arrangement of birefringent elements is followed by a retrodirective element so that the radiation emerging from the series arrangement after being reflected traverses the series arrangement in the opposite direction.
  • the series arrangement needs only comprise at least two birefringent elements.
  • the voltage applied to the crystals can be lower.
  • FIGS. I and 2 show, by way of example, embodiments of apparatuses according to the invention.
  • FIG. 1 natural radiation emitted from a source 1 of radiation is collimated by a lens 2 and converted by a polarizer 3 into linearly plane polarized radiation. For simplicity only one ray of the beam of radiation is shown. After passing through a semitransparent mirror 4 the plane polarized radiation passes through the series arrangement of two electro-optical crystals 5 and 8 which exhibit the Pockels effect and the principal directions of which, which are indicated by arrows 6 and 9, are at an angle of 45 to one another.
  • the voltages V and V, are applied so that the electric fields generated by them in the crystals 5 and 8 respectively are parallel to the direction of propagation of the light in the respective crystal.
  • the radiation emerging from the crystal 8 is reflected at a plane mirror II.
  • the radiation then passes through the crystals 8 and 5 in the opposite direction and is reflected by the semitransparent mirror 4 to a photoelectric detection system I2.
  • the beam reflected at the mirror I] has again been shown by one ray which for clarity had been shifted relative to the ray incident on the mirror 11.
  • the amplitude V of the voltage applied to the crystal 5 is such that linearly polarized radiation incident on the crystal 5 is converted into circularly polarized radiation, for the value of V is chosen to be such that a phase difference of a quarter wavelength is produced between two oscillations which are created from linearly polarized light when it passes through the respective crystal.
  • the amplitude V' of the voltage applied to the crystal 8 is chosen to be such that a phase difference of a half wavelength is produced between the two oscillations which are created from linearly polarized light when it passes through the crystal 8 at a voltage of2 v.
  • the crystals 5 and 8 together with their respective mirror images with respect to the reflector II may each effectively be considered as one crystal.
  • the apparatus shown in FIG. I has the same properties as that shown in FIG. I of the U.S. Pat. No. 3,558,2l5 for the crystal 5 of the new arrangement corresponds to the crystal 4 of the main application, the crystal 8 together with its mirror image corresponds to the crystal 5, and the mirror image of the crystal 5 corresponds to the crystal 6 of the main application.
  • the amplitude of the voltage applied to the crystal 8 is only one half of that applied to the crystal 5 of FIG. I of the main application.
  • the phases of the alternating voltages applied to the crystal 5 and to its mirror image automatically are identical. Hence, no adjusting difficulties will occur.
  • the wavelength A of the radiation was 6,328 AU.
  • the radiation emerging from the crystal 27 is reflected at a plane mirror 30.
  • the radiation then traverses the crystal 27 and the M4 plate 25 in the opposite direction and is reflected to a photoelectric detection system 31 by the semitransparent mirror 24.
  • a source 29 To the crystal 27 there is applied from a source 29 a sawtooth voltage in which the difference between the maximum 7 and minimum values is such as to produce a phase difference of one-half wavelength between the two oscillations which are created from linearly polarized light on its passage through the crystal 27.
  • the crystal 27 together with its mirror image with respect to the reflector 30 may again be considered as one crystal.
  • the apparatus shown in FIG. 2 has the same properties as the apparatus shown in FIG. 4 of the main application, for the M4 plate 25 correspondsto the M4 plate 25 of FIG. 4, the crystal 27 together with its mirror image corresponds to the crystal 26 of FIG. 4 and the mirror image of the M4 plate 25 corresponds to the M4 plate 27 of FIG. 4.
  • the difference between the maximum and minimum values of the sawtooth voltage applied to the crystal 27 is only one half of the corresponding difference of the voltage applied to the crystal 26 of FIG. 4 of the main application.
  • a cat's eye is composed of a lens and a plane or concave mirror located in the focal plane of the lens.
  • An apparatus for converting radiation having an arbitrary plane of polarization into linearly polarized radiation having a plane of polarization varying linearly with time with respect to an initial arbitrary orientation comprising polarizing means in the path of a beam of radiation having an arbitrary plane of polarization for converting the plane of polarization of the beam into a linearly polarized beam having a stationary plane of polarization, a first birefringent element in the path of the plane polarized radiation from the polarizer, an electro-optisource of alternating voltage applied across the electro-optical crystal.
  • birefringent element comprises a M4 plate.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
US7634A 1969-02-03 1970-02-02 Apparatus for converting linearly polarized radiation into linearly polarized radiation having a plane of polarization varying linearly with time Expired - Lifetime US3630595A (en)

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NL6901722A NL6901722A (US20100223739A1-20100909-C00025.png) 1969-02-03 1969-02-03

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US3630595A true US3630595A (en) 1971-12-28

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US (1) US3630595A (US20100223739A1-20100909-C00025.png)
AU (1) AU1090370A (US20100223739A1-20100909-C00025.png)
BE (1) BE745367R (US20100223739A1-20100909-C00025.png)
CA (1) CA964359A (US20100223739A1-20100909-C00025.png)
DE (1) DE2003975A1 (US20100223739A1-20100909-C00025.png)
FR (1) FR2037350A6 (US20100223739A1-20100909-C00025.png)
GB (1) GB1292205A (US20100223739A1-20100909-C00025.png)
NL (1) NL6901722A (US20100223739A1-20100909-C00025.png)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3740663A (en) * 1970-12-21 1973-06-19 Raytheon Co Q-switched laser system
US3900247A (en) * 1974-02-26 1975-08-19 Northern Electric Co Optical modulator having compensation for thermal and space charge effects
US4318591A (en) * 1980-06-10 1982-03-09 Ford Aerospace & Communications Corp. Polarization switched image rotator
US4767196A (en) * 1985-11-27 1988-08-30 American Telephone And Telegraph Company, At&T Bell Laboratories Asymmetric optical logic element

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2184253A (en) * 1985-12-13 1987-06-17 Stc Plc Optical state-of-polarisation modulator
GB2203259A (en) * 1987-02-26 1988-10-12 Plessey Co Plc Polarisation rotator associated with reflective surface

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3239671A (en) * 1962-05-21 1966-03-08 Gen Telephone & Elect Single-sideband light modulator
US3432223A (en) * 1963-04-10 1969-03-11 Nippon Electric Co Modulator for a light beam

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3239671A (en) * 1962-05-21 1966-03-08 Gen Telephone & Elect Single-sideband light modulator
US3432223A (en) * 1963-04-10 1969-03-11 Nippon Electric Co Modulator for a light beam

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Takasaki, Photometric Measurement of Polarized Light by Means of ADP Polarization Modulator I J.O.S.A. Vol. 51, No. 4 (Apr. 1951) pp. 462 463 *
Takasaki, Photometric Measurement of Polarized Light by Means of ADP Polarization Modulator II J.O.S.A. Vol. 51, No. 4 (Apr. 1961) p. 463 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3740663A (en) * 1970-12-21 1973-06-19 Raytheon Co Q-switched laser system
US3900247A (en) * 1974-02-26 1975-08-19 Northern Electric Co Optical modulator having compensation for thermal and space charge effects
US4318591A (en) * 1980-06-10 1982-03-09 Ford Aerospace & Communications Corp. Polarization switched image rotator
US4767196A (en) * 1985-11-27 1988-08-30 American Telephone And Telegraph Company, At&T Bell Laboratories Asymmetric optical logic element

Also Published As

Publication number Publication date
DE2003975A1 (de) 1970-08-06
BE745367R (US20100223739A1-20100909-C00025.png) 1970-08-03
AU1090370A (en) 1971-08-05
CA964359A (en) 1975-03-11
NL6901722A (US20100223739A1-20100909-C00025.png) 1970-08-05
FR2037350A6 (US20100223739A1-20100909-C00025.png) 1970-12-31
GB1292205A (en) 1972-10-11

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